1. Field of the Invention
The present invention relates to the production of itaconic acid by the microbial fermentation of carbohydrates, and, more especially, by a microbiological process comprising the conversion of sugars derived from starch.
2. Description of the Prior Art
The synthesis of organic acids by the fermentation of sugars in the presence of appropriate microorganisms has long been known to this art. Typical acids prepared by microbial fermentation include, in particular, acetic acid, lactic acid, citric acid, gluconic and 2-ketogluconic acids, fumaric acid, and itaconic acid. These acids are useful in the food, pharmaceutical, chemical and other industries. Such preparative processes are described, for example, in the text, Chemicals by Fermentation, S. J. Gutcho, Noyes Data Corporation (1973).
In industrial fermentations, the selection of the carbon source is based on its availability, its cost and its ability to permit high productivity. Starch is often specified as an inexpensive source of carbon. However, not all microorganisms are capable of metabolizing starch, while the majority metabolize dextrose. Consequently, the starch must be hydrolyzed/saccharified prior to fermentation. Overall production is thereby markedly reduced.